真空热处理碳纳米管的储氢性能研究

研究了真空热处理对多壁碳纳米管(MWNTs)电化学储氢性能的影响.采用化学气相沉积法(CVD)制备碳纳米管，碳纳米管与LaNi₅储氢合金按质量比1∶10混合，制作成CNTs-LaNi₅电极.电解池采用三电极体系，6mol/L KOH为电解液，Ni(OH)₂为正极，Hg/HgO为参比电极.实验结果表明，在相同的充放电条件下，850℃时CNTs-LaNi₅电极的储氢性能最好，克容量最大为503.6mAh/g，相应的平台电压高达1.18V.从500—850℃随着温度升高，放电量有较大幅度的增加，但到950℃时放电量反而下降.由此可见，碳纳米管的热处理温度对碳纳米管的电化学储氢性能有着较大的影响. 关键词： 碳纳米管(CNTs) 储氢性能 5合金')" href="#">LaNi₅合金 化学气相沉积法(CVD法)

Hydrogen storage properties of CNTs treated at different temperature in vacuum

The effect of multi-wall nanotubes (MWNTs) treated at different temperature in vacuum on the electrochemical hydrogen storage properties were investigated. The MWNTs were synthesized by chemical vapor deposition. The CNTs(carbon nanotubes)-LaNi₅ electrodes were prepared by mixing MWNTs and LaNi₅ alloy in a weight ratio of 1∶10. Three-electrode system was introduced. The CNTs-LaNi₅ electrodes were used as the working electrode. Ni(OH)₂/NiOOH worked as the counter electrode and Hg/HgO as the reference electrode. 6mol/L KOH solution acted as the electrolyte. Results showed that the CNTs-LaNi₅ electrodes with CNTs treated at 850℃ in vacuum has the best electrochemical hydrogen storage capacity with a maximum discharging capacity of 503.6mAh/g and a corresponding discharging plateau voltage of 1.18V under the same testing condition. From 500℃ to 850℃, the higher the temperature of heating, the better the electrochemical hydrogen storage property of WMNTs. However, CNTs-LaNi₅ electrodes with CNTs treated at 950℃ in vacuum has lower discharging capacity under the same testing condition. This shows that the temperature of CNTs treatment in vacuum is an important factor that influences its electrochemical hydrogen storage performance.